y other man. With it he isolated
fluorine, most active of the elements, and he prepared for the first
time in their purity many of the rare metals that have since found
industrial employment. He also made the carbides of the various metals,
including the now common calcium carbide. Among the problems that he
undertook and solved was the manufacture of artificial diamonds. He
first made pure charcoal by burning sugar. This was packed with iron in
the hollow of a block of lime into which extended from opposite sides
the carbon rods connected to the dynamo. When the iron had melted and
dissolved all the carbon it could, Moissan dumped it into water or
better into melted lead or into a hole in a copper block, for this
cooled it most rapidly. After a crust was formed it was left to solidify
slowly. The sudden cooling of the iron on the outside subjected the
carbon, which was held in solution, to intense pressure and when the bit
of iron was dissolved in acid some of the carbon was found to be
crystallized as diamond, although most of it was graphite. To be sure,
the diamonds were hardly big enough to be seen with the naked eye, but
since Moissan's aim was to make diamonds, not big diamonds, he ceased
his efforts at this point.

To produce large diamonds the carbon would have to be liquefied in
considerable quantity and kept in that state while it slowly
crystallized. But that could only be accomplished at a temperature and
pressure and duration unattainable as yet. Under ordinary atmospheric
pressure carbon passes over from the solid to the gaseous phase without
passing through the liquid, just as snow on a cold, clear day will
evaporate without melting.

Probably some one in the future will take up the problem where Moissan
dropped it and find out how to make diamonds of any size. But it is not
a question that greatly interests either the scientist or the
industrialist because there is not much to be learned from it and not
much to be made out of it. If the inventor of a process for making
cheap diamonds could keep his electric furnace secretly in his cellar
and market his diamonds cautiously he might get rich out of it, but he
would not dare to turn out very large stones or too many of them, for if
a suspicion got around that he was making them the price would fall to
almost nothing even if he did sell another one. For the high price of
the diamond is purely fictitious. It is in the first place kept up by
limiting the ou